OFFSET
1,1
COMMENTS
REFERENCES
Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, p. 14.
LINKS
Clark Kimberling, Table of n, a(n) for n = 1..1000
EXAMPLE
Approximations are shown here:
n ... ((n+1)/(n-1))^n - e^2 ... 1/n^2
2 ... 1.610943901 ............. 0.25
3 ... 0.610943901 ............. 0.11111
4 ... 0.326993283 ............. 0.0625
5 ... 0.204693901 ............. 0.04
6 ... 0.140479901 ............. 0.02777
a(2) = 5 because p(5) - e^2 < 1/4 < p(4) - e^2.
MATHEMATICA
z = 1200; p[k_] := p[k] = ((k + 1)/(k - 1))^k; (* Finch p. 15 *);
N[Table[p[n] - E^2, {n, 2, z/20}]]
f[n_] := f[n] = Select[Range[z], # > 1 && p[#] - E^2 < 1/n^2 &, 1]
u = Flatten[Table[f[n], {n, 1, z/4}]] (* A248106 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Oct 02 2014
STATUS
approved